Photoelectric detector devices of that kind, are known in the field of the atomic absorption spectroscopy, for instance in the form of photo semiconductor devices.
The photo semiconductor devices in a detector device of that kind may exist in the form of photo diodes, CCD structures etc.
However, the signal/noise ratio of known detector devices of that kind depends on the portion of the detector face that is actually loaded by a radiation to be detected. An aggravated signal/noise ratio in particular results if not the entire detector face but only a small part thereof is loaded by the radiation to be detected.